METHOD OF DRILLING DEEP OPENINGS OF SMALL DIAMETER, AND BLADED DRILL OF ONE-WAY CUTTING Russian patent published in 2001 - IPC

FIELD: mechanical engineering, producing arrangement of accurate coordinate openings in housing parts of hunting weapon. SUBSTANCE: method contains machining of pilot opening by means of ordinary drill and following drilling by bladed drill of one-way cutting. The bladed drill contains one blade provided with cutting edge which has reversed sharpening and auxiliary cutting edge. To provide interchangeability of units and parts of hunting weapon and to reduce adjustment operations when assembling it the pilot opening is made to a depth which is not less than double height of the cutting edge of the bladed drill. The opening is drilled through by ordinary drill of diameter less than undersize diameter of the machined opening. The finishing treatment is carried out with one blade of the bladed drill which top is aligned with a circumference formed by drill diameter. Constant uniform pressure is applied to the cutting edge to press the auxiliary cutting edge to the wall of the machined opening. The cutting edge of the bladed drill is inclined at an angle of 45 deg. and the auxiliary cutting edge is of the drill is at an angle of 0 deg. EFFECT: improved method. 2 cl, 3 dwg